Effects of blood lead levels on airflow limitations in Korean adults: findings from the 5th KNHNES 2011

This study aimed to examine whether blood levels of heavy metals, such as lead, mercury and cadmium, are related with pulmonary function in Korean adults. This investigation included 870 Korean adults (≥ 40 years) who received pulmonary function testing in the Korea National Health and Nutrition Examination Survey (KNHANES) V-2, 2011. Data of blood levels of heavy metals, pulmonary function tests and anthropometric measurements were acquired. Blood lead levels showed inverse correlations with the FEV1/FVC ratio before (r = -0.276, p < 0.001) and after adjustment of multiple compounding factors (r = -0.115, p = 0.001). A logistic multiple regression analysis revealed that blood lead levels were a significant influencing factor for the FEV1/FVC ratio (β = -0.017, p = 0.001, adjusted R(2) = 0.267). The odds ratios (ORs) for the FEV1/FVC ratio were significantly lower in the highest tertile group of the blood lead levels than in the lowest tertile group in Model 1 (OR = 0.007, 95% CI = 0.000-0.329) and Model 2 (OR = 0.006, 95% CI = 0.000-0.286). These findings imply that environmental exposure to lead might be an important factor that may cause airflow limitations in Korean adults.

Effects of pentoxifylline on proteinuria and glucose control in patients with type 2 diabetes: a prospective randomized double-blind multicenter study

BACKGROUND

Pentoxifylline is a methylxanthine derivative with significant anti-inflammatory, anti-fibrotic, and anti-proliferative properties. Studies have shown that pentoxifylline may have renoprotective effects in patients with diabetic nephropathy. However, most of these studies were limited by small sample sizes. Therefore, we investigated whether pentoxifylline could reduce proteinuria in patients with diabetic nephropathy and residual proteinuria who received an angiotensin-converting enzyme inhibitor (ACEI) or an angiotensin II receptor blocker (ARB). We also studied the effects of pentoxifylline on glycemic control, insulin resistance, and inflammatory parameters.

METHODS

This was a prospective, randomized double-blind, placebo-controlled, multi-center study. A total of 174 patients with type 2 diabetes and albuminuria (>30 mg/g of creatinine) who were taking the recommended dosage of ACEI or ARB for > 6 months and receiving conventional therapy for diabetes were randomly assigned to receive pentoxifylline (1200 mg, daily; n = 87) or a placebo (n = 87) for 6 months. The endpoints were the effects of pentoxifylline on proteinuria, renal function, glucose control, and inflammatory parameters.

RESULTS

The percentage changes in proteinuria from baseline in the pentoxifylline and placebo groups were a decrease of 23 % and 4 %, respectively (p = 0.012). In addition, significant reductions in fasting plasma glucose, glycated hemoglobin, and insulin resistance according to the homeostasis model assessment were observed in the pentoxifylline group compared to those in the placebo group. However there was no significant difference in serum tumor necrosis factor (TNF)-α between the groups.

CONCLUSIONS

Pentoxifylline therapy reduced proteinuria and improved glucose control and insulin resistance without significant change of serum TNF-α in patients with type 2 diabetic nephropathy. Therefore, pentoxifylline is a potential therapeutic alternative for treating diabetes and diabetic nephropathy.

TRIAL REGISTRATION

NCT01382303.

Composition of dietary macronutrient intake is not associated with prevalence of coronary artery calcification in healthy Korean adults

BACKGROUND AND AIMS

There is little information supporting the relationships between macronutrients and pre-clinical atherosclerosis. The aim of this study was to identify whether dietary macronutrient content is related with CAC.

METHODS

10,793 healthy Korean adults in a cohort were enrolled. Subjects were divided into CAC (CAC score >0) or non-CAC group (CAC score = 0). Intake of energy, carbohydrate (CHO), protein and fat were obtained using food frequency questionnaire (FFQ). Macronutrient composition was expressed as the ratio of energy from each macronutrient to total energy. Subjects were classified into three groups according to tertiles of intake for each macronutrient. To investigate the association between macronutrient intake and CAC, multiple regression analysis was conducted according to tertile groups of each macronutrient.

RESULTS

The prevalence of CAC significantly differed among tertile groups of CHO and fat intake in men (p < 0.001, p < 0.01) and women (p < 0.05, p < 0.01). However, multiple logistic regression analysis revealed that the odds ratios (ORs) for CAC were not significantly different among tertile groups of each macronutrient intake after adjustment in men (CHO: OR = 0.965 [95% CI = 0.826-1.129]; protein: OR = 1.029 [95% CI = 0.881-1.201]; fat: OR = 1.015 [95% CI = 0.868-1.188]) and women (CHO: OR = 1.158 [95% CI = 0.550-2.438]; protein: OR = 1.261 [95% CI = 0.629-2.528]; fat: OR = 0.625 [95% CI = 0.286-1.365]).

CONCLUSIONS

The prevalence of CAC may not be associated with composition of dietary macronutrient intake in in healthy Korean adults.

The Effect of DPP-4 Inhibitors on Metabolic Parameters in Patients with Type 2 Diabetes

BACKGROUND

We evaluated the effects of two dipeptidyl peptidase-4 (DPP-4) inhibitors, sitagliptin and vildagliptin, on metabolic parameters in patients with type 2 diabetes mellitus.

METHODS

A total of 170 type 2 diabetes patients treated with sitagliptin or vildagliptin for more than 24 weeks were selected. The patients were separated into two groups, sitagliptin (100 mg once daily, n=93) and vildagliptin (50 mg twice daily, n=77). We compared the effect of each DPP-4 inhibitor on metabolic parameters, including the fasting plasma glucose (FPG), postprandial glucose (PPG), glycated hemoglobin (HbA1c), and glycated albumin (GA) levels, and lipid parameters at baseline and after 24 weeks of treatment.

RESULTS

The HbA1c, FPG, and GA levels were similar between the two groups at baseline, but the sitagliptin group displayed a higher PPG level (P=0.03). After 24 weeks of treatment, all of the glucose-related parameters were significantly decreased in both groups (P=0.001). The levels of total cholesterol and triglycerides were only reduced in the vildagliptin group (P=0.001), although the sitagliptin group received a larger quantity of statins than the vildagliptin group (P=0.002).The mean change in the glucose- and lipid-related parameters after 24 weeks of treatment were not significantly different between the two groups (P=not significant). Neither sitagliptin nor vildagliptin treatment was associated with a reduction in the high sensitive C-reactive protein level (P=0.714).

CONCLUSION

Vildagliptin and sitagliptin exert a similar effect on metabolic parameters, but vildagliptin exerts a more potent beneficial effect on lipid parameters.

The role of insulin resistance in diabetic neuropathy in Koreans with type 2 diabetes mellitus: a 6-year follow-up study

PURPOSE

We previously reported that insulin resistance, low high-density lipoprotein (HDL) cholesterol, and glycaemic exposure Index are independently associated with peripheral neuropathy in Korean patients with type 2 diabetes mellitus. We followed the patients who participated in that study in 2006 for another 6 years to determine the relationship between insulin resistance and neuropathy.

MATERIALS AND METHODS

This study involved 48 of the original 86 Korean patients with type 2 diabetes mellitus who were referred to the Neurology clinic for the assessment of diabetic neuropathy from January 2006 to December 2006. These 48 patients received management for glycaemic control and prevention of diabetic complications in the outpatient clinic up to 2012. We reviewed blood test results and the nerve conduction study findings of these patients, taken over a 6-year period.

RESULTS

Low HDL cholesterol and high triglycerides significantly influenced the development of diabetic neuropathy. Kitt value (1/insulin resistance) in the previous study affected the occurrence of neuropathy, despite adequate glycaemic control with HbA1c <7%. Insulin resistance affected the development of diabetic neuropathy after 6 years: insulin resistance in 2006 showed a positive correlation with a change in sural sensory nerve action potential in 2012.

CONCLUSION

Diabetic neuropathy can be affected by previous insulin resistance despite regular glycaemic control. Dyslipidaemia should be controlled in patients who show high insulin resistance because HDL cholesterol and triglycerides are strongly correlated with later development of diabetic neuropathy.

Subclinical vascular inflammation in subjects with normal weight obesity and its association with body fat: an 18 F-FDG-PET/CT study

Background

Although body mass index (BMI) is the most widely accepted parameter for defining obesity, recent studies have indicated a unique set of patients who exhibit normal BMI and excess body fat (BF), which is termed as normal weight obesity (NWO). Increased BF is an established risk factor for atherosclerosis. However, it is unclear whether NWO subjects already have a higher degree of vascular inflammation compared to normal weight lean (NWL) subjects; moreover, the association of BF with vascular inflammation in normal weight subjects is largely unknown.

Methods

NWO and NWL subjects (n = 82 in each group) without any history of significant vascular disease were identified from a 3-year database of consecutively recruited patients undergoing ¹⁸ F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸ F-FDG-PET/CT) at a self-referred Healthcare Promotion Program. The degree of subclinical vascular inflammation was evaluated using the mean and maximum target-to-background ratios (TBRmean and TBRmax) of the carotid artery, which were measured by ¹⁸ F-FDG-PET/CT (a noninvasive tool for assessing vascular inflammation).

Results

We found that metabolically dysregulation was greater in NWO subjects than in NWL subjects, with a significantly higher blood pressure, higher fasting glucose level, and worse lipid profile. Moreover, NWO subjects exhibited higher TBR than NWL subjects (TBRmean: 1.33 ± 0.16 versus 1.45 ± 0.19, p < 0.001; TBRmax: 1.52 ± 0.23 versus 1.67 ± 0.25, p < 0.001). TBR was significantly associated with total BF (TBRmean: r = 0.267, p = 0.001; TBRmax: r = 0.289, p < 0.001), age (TBRmean: r = 0.170, p = 0.029; TBRmax: r = 0.165, p = 0.035), BMI (TBRmean: r = 0.184, p = 0.018; TBRmax: r = 0.206, p = 0.008), and fasting glucose level (TBRmean: r = 0.157, p = 0.044; TBRmax: r = 0.182, p = 0.020). In multiple linear regression analysis, BF was an independent determinant of TBRmean and TBRmax, after adjusting for age, BMI, and fasting glucose level (TBRmean: regression coefficient = 0.020, p = 0.008; TBRmax: regression coefficient = 0.028, p = 0.005). Compared to NWL, NWO was also independently associated with elevated TBRmax values, after adjusting for confounding factors (odds ratio = 2.887, 95% confidence interval 1.206–6.914, p = 0.017).

Conclusions

NWO is associated with a higher degree of subclinical vascular inflammation, of which BF is a major contributing factor. These results warrant investigations for subclinical atherosclerosis in NWO patients.

Postprandial C-peptide to glucose ratio as a predictor of β-cell function and its usefulness for staged management of type 2 diabetes

Aims/Introduction

Type 2 diabetes is characterized by progressive deterioration of β‐cell function. Recently, it was suggested that the C‐peptide‐to‐glucose ratio after oral glucose ingestion is a better predictor of β‐cell mass than that during fasting. We investigated whether postprandial C‐peptide‐to‐glucose ratio (PCGR) reflects β‐cell function, and its clinical application for management of type 2 diabetes.

Materials and Methods

We carried out a two‐step retrospective study of 919 Korean participants with type 2 diabetes. In the first step, we evaluated the correlation of PCGR level with various markers for β‐cell function in newly diagnosed and drug‐naïve patients after a mixed meal test. In the second step, participants with well‐controlled diabetes (glycated hemoglobin <7%) were divided into four groups according to treatment modality (group I: insulin, group II: sulfonylurea and/or dipeptityl peptidase IV inhibitor, group III: metformin and/or thiazolidinedione and group IV: diet and exercise group).

Results

In the first step, PCGR was significantly correlated with various insulin secretory indices. Furthermore, PCGR showed better correlation with glycemic indices than homeostatic model assessment of β‐cell function (HOMA‐β). In the second step, the PCGR value significantly increased according to the following order: group I, II, III, and IV after adjusting for age, sex, body mass index and duration of diabetes. The cut‐off values of PCGR for separating each group were 1.457, 2.870 and 3.790, respectively (P < 0.001).

Conclusions

We suggest that PCGR might be a useful marker for β‐cell function and an ancillary parameter in the choice of antidiabetic medication in type 2 diabetes.

Transplantation of insulin-secreting cells differentiated from human adipose tissue-derived stem cells into type 2 diabetes mice

Currently, there are limited ways to preserve or recover insulin secretory capacity in human pancreas. We evaluated the efficacy of cell therapy using insulin-secreting cells differentiated from human eyelid adipose tissue-derived stem cells (hEAs) into type 2 diabetes mice. After differentiating hEAs into insulin-secreting cells (hEA-ISCs) in vitro, cells were transplanted into a type 2 diabetes mouse model. Serum levels of glucose, insulin and c-peptide were measured, and changes of metabolism and inflammation were assessed in mice that received undifferentiated hEAs (UDC group), differentiated hEA-ISCs (DC group), or sham operation (sham group). Human gene expression and immunohistochemical analysis were done. DC group mice showed improved glucose level, and survival up to 60 days compared to those of UDC and sham group. Significantly increased levels of human insulin and c-peptide were detected in sera of DC mice. RT-PCR and immunohistochemical analysis showed human gene expression and the presence of human cells in kidneys of DC mice. When compared to sham mice, DC mice exhibited lower levels of IL-6, triglyceride and free fatty acids as the control mice. Transplantation of hEA-ISCs lowered blood glucose level in type 2 diabetes mice by increasing circulating insulin level, and ameliorating metabolic parameters including IL-6.

Serum adiponectin and type 2 diabetes: a 6-year follow-up cohort study

BACKGROUND

Studies on factors which may predict the risk of diabetes are scarce. This prospective cohort study was conducted to determine the association between adiponectin and type 2 diabetes among Korean men and women.

METHODS

A total of 42,845 participants who visited one of seven health examination centers located in Seoul and Gyeonggi province, Republic of Korea between 2004 and 2008 were included in this study. The incidence rates of diabetes were determined through December 2011. To evaluate the effects of adiponectin on type 2 diabetes, the Cox proportional hazard model was used.

RESULTS

Of the 40,005 participants, 959 developed type 2 diabetes during a 6-year follow-up. After the adjustment for age, body mass index (BMI), and waist circumference, the risks for type 2 diabetes in participants with normoglycemia had a 1.70-fold (95% confidence interval [CI], 1.21 to 2.38) increase in men and a 1.83-fold (95% CI, 1.17 to 2.86) increase in women with the lowest tertile of adiponectin when compared to the highest tertile of adiponectin. For participants with impaired fasting glucose (IFG), the risk for type 2 diabetes had a 1.46-fold (95% CI, 1.17 to 1.83) increase in men and a 2.52-fold (95% CI, 1.57 to 4.06) increase in women with the lowest tertile of adiponectin. Except for female participants with normoglycemia, all the risks remained significant after the adjustment for fasting glucose and other confounding variables. Surprisingly, BMI and waist circumference were not predictors of type 2 diabetes in men or women with IFG after adjustment for fasting glucose and other confounders.

CONCLUSION

A strong association between adiponectin and diabetes was observed. The use of adiponectin as a predictor of type 2 diabetes is considered to be useful.

Diabetes epidemics in Korea: reappraise nationwide survey of diabetes "diabetes in Korea 2007"

There are many studies on the prevalence, clinical characteristics, and economic burden of diabetes across the past four decades in Korea. Nonetheless, there is a dearth of nationwide study regarding diabetes encompassing all age group. Eight years ago, the Committee on the Epidemiology of Diabetes Mellitus of Korean Diabetes Association collaborated with Health Insurance Review & Assessment Service to evaluate the status of diabetes care and characteristics in diabetic patients in Korea. In 2007, the collaborative task force team published a comprehensive survey titled "Diabetes in Korea 2007." In this review, we reappraise the diabetic epidemics from the joint report and suggest further studies that are needed to be investigated in the future.

Beneficial Effects of Omega-3 Fatty Acids on Low Density Lipoprotein Particle Size in Patients with Type 2 Diabetes Already under Statin Therapy

Beyond statin therapy for reducing low density lipoprotein cholesterol (LDL-C), additional therapeutic strategies are required to achieve more optimal reduction in cardiovascular risk among diabetic patients with dyslipidemia. To evaluate the effects and the safety of combined treatment with omega-3 fatty acids and statin in dyslipidemic patients with type 2 diabetes, we conducted a randomized, open-label study in Korea. Patients with persistent hypertriglyceridemia (≥200 mg/dL) while taking statin for at least 6 weeks were eligible. Fifty-one patients were randomized to receive either omega-3 fatty acid 4, 2 g, or no drug for 8 weeks while continuing statin therapy. After 8 weeks of treatment, the mean percentage change of low density lipoprotein (LDL) particle size and triglyceride (TG) level was greater in patients who were prescribed 4 g of omega-3 fatty acid with statin than in patients receiving statin monotherapy (2.8%±3.1% vs. 2.3%±3.6%, P=0.024; -41.0%±24.1% vs. -24.2%±31.9%, P=0.049). Coadministration of omega-3 fatty acids with statin increased LDL particle size and decreased TG level in dyslipidemic patients with type 2 diabetes. The therapy was well tolerated without significant adverse effects.

Variants of the adiponectin gene and diabetic microvascular complications in patients with type 2 diabetes

OBJECTIVE

The aim of this study was to examine the association between common polymorphisms of the adiponectin gene (ADIPOQ) and microvascular complications in patients with type 2 diabetes mellitus (T2DM).

RESEARCH DESIGN AND METHODS

Rs2241766 and rs1501299 of ADIPOQ were genotyped in 708 patients with T2DM. Fundus photography, nerve conducting velocity, and urine analysis were performed to check for the presence of microvascular complications including diabetic nephropathy, retinopathy and neuropathy.

RESULTS

The prevalence of diabetic nephropathy tended to be different according to rs2241766 genotype (p=0.057) and the GG genotype of rs2241766 was associated with diabetic nephropathy [urine albumin/creatinine ratio (UACR) greater than 30 mg/g] after adjusting for age, sex, body mass index, duration of diabetes, HDL-cholesterol, smoking status, and blood pressure (odds ratio=1.96; 95% confidence interval=1.01-3.82, p=0.049). Also, the G allele of rs2241766 demonstrated a trend to be associated with an increase in UACR (p=0.087). Rs2241766 genotype was not associated with diabetic retinopathy (p=0.955) and neuropathy (p=0.104) or any diabetic microvascular complications (p=0.104). There was no significant association between the rs1501299 genotype of ADIPOQ and the prevalence of diabetic retinopathy and neuropathy or any diabetic microvascular complications even after adjustment.

CONCLUSION

These data suggest that the GG genotype at rs2241766 is implicated in the pathogenesis of risk for diabetic nephropathy defined as UACR greater than 30 mg/day in patients with T2DM.

Efficacy and safety of glimepiride/metformin sustained release once daily vs. glimepiride/metformin twice daily in patients with type 2 diabetes

AIMS

The study investigated the clinical equivalence in reducing haemoglobin A1c (A1C) between glimepiride/metformin sustained release (GM-SR) 2/500 mg, a fixed-dose combination, once daily and glimepiride/metformin (GM) 1/250 mg, a fixed-dose combination, twice daily in patients with type 2 diabetes (T2D).

METHODS

A multicentre, randomised, double-blind, double-dummy study was conducted in 14 hospitals in Korea. Inclusion criteria were age 30-75 years, T2D diagnosis no longer than 10 years previously, A1C between 7% and 10%, and body mass index <40 kg/m(2) . A total of 207 subjects were randomised into the GM-SR group (n=101) or the GM group (n=106). Participants were assessed at baseline, 8 weeks and 16 weeks after treatment.

RESULTS

After 16 weeks treatment, no difference in baseline-adjusted changes of A1C (primary efficacy variable) was observed between the two groups (-0.59% for GM-SR group vs. -0.61% for GM group, 95% CI: -0.17 to 0.21; p=0.84). In addition, there were no significant differences in secondary efficacy parameters between the two groups, including changes in A1C up to week 8, changes in fasting plasma glucose (FPG) and 2-h-postprandial plasma glucose up to week 8 and week 16, response rate, drug compliance and hypoglycaemic events. However, there was a difference in baseline-adjusted changes of FPG between the two groups (-1.01 mmol/l for GM-SR group vs. -1.52 mmol/l for GM group, p=0.01 in the intention to treat set).

CONCLUSIONS

GM-SR 2/500 mg once daily was as effective as GM 1/250 mg twice daily in lowering A1C. In addition, no difference was noted in hypoglycaemic events between the two groups.

Resolution of type 2 diabetes after gastrectomy for gastric cancer with long limb Roux-en Y reconstruction: a prospective pilot study

PURPOSE

It is unclear whether metabolic surgery is effective in non obese type 2 diabetes mellitus (T2DM) and the result after gastrectomy and conventional reconstruction for gastric cancer with non obese T2DM are not satisfactory for improvement of T2DM. Prospective single-arm pilot study with long limb Roux-en Y reconstruction after gastrectomy was evaluated on its safety and efficacy as a potential cure for T2DM in patients with non obese gastric cancer.

METHODS

Fifteen patients with non obese T2DM and gastric cancer were enrolled. After gastrectomy, the gastrointestinal tract was reconstructed by Roux-en Y gastrojejunostomy or esophagojejunostomy. The biliopancreatic and Roux limb were 100 to 120 cm long each.

RESULTS

There was no surgery-related mortality, but four cases experienced complications (26.7%). Before surgery, the mean body mass index was 25.2 ± 3.4 kg/m(2) and mean glycated hemoglobin (HbA1c) was 7.7 ± 1.4% with antidiabetic medications. The mean BMI decreased to 21.7 ± 3.1 kg/m(2) (P < 0.05) and the mean HbA1c decreased to 6.3 ± 0.8% (P < 0.05) 6 months after surgery. At the end of the study (follow-up duration, 12.5 ± 5.5 months), HbA1c decreased to <6% in 11 patients (78.6%) without any antidiabetic medications. There were no patients who had anemia, and/or malnutrition after surgery except one patient who died due to recurrence four months after surgery.

CONCLUSION

Long limb Roux-en Y reconstruction after gastrectomy is feasible and has the potential to cure T2DM in non obese gastric cancer patients. A randomized controlled trial is needed to confirm this result.

Gastrectomy for early gastric cancer is associated with decreased cardiovascular mortality in association with postsurgical metabolic changes

BACKGROUND

Bariatric surgery effectively induces weight loss and resolves cardiovascular comorbidities in obese patients. We investigated cardiovascular and all-cause mortality in patients who underwent gastrectomies for early gastric cancer (EGC) and analyzed the changes in metabolic parameters after surgery.

METHODS

A total of 2,477 patients who underwent gastrectomies for EGC between 1995 and 2004 were enrolled in the study and followed for mortality through 2007. Standardized mortality ratios (SMRs) were calculated using sex- and age-matched mortality in the general Korean population in 2005. Effects of gastrectomy on changes in body weight and metabolic parameters were investigated in 51 of the patients before and after surgery.

RESULTS

During the 15,096.4 person-years of follow-up, 244 deaths were recorded. The all-cause mortality was not significantly different from that of the general population (SMR [95 % confidence interval (CI)] = 1.01 [0.89 - 1.14]); however, cardiovascular mortality was significantly lower (SMR = 0.35 [0.22 - 0.53]). In the 51 patients included in the second part of the study, significant reductions in body weight and visceral fat areas occurred after surgery, regardless of whether the patients were previously obese. Triglycerides, LDL-cholesterol, and plasminogen activator inhibitor-1 levels were significantly decreased, whereas HDL-cholesterol and adiponectin levels were increased. Carotid intima-media thickness also was significantly decreased in previously obese and nonobese patients.

CONCLUSIONS

Patients with EGC who undergo gastrectomy have a lower cardiovascular mortality but similar all-cause mortality as that of the general population. In these patients, a significant reduction in body weight and visceral fat after surgery may improve impaired lipid metabolism and prevent atherosclerotic changes.

Efficacy and safety of exenatide once-weekly vs exenatide twice-daily in Asian patients with type 2 diabetes mellitus

AIMS/INTRODUCTION

To compare safety and efficacy of the extended-release formulation exenatide once weekly (EQW) vs exenatide twice daily (EBID) for 26 weeks in type 2 diabetes patients from China, India, Japan, South Korea and Taiwan.

MATERIALS AND METHODS

A randomized, comparator-controlled, open-label study included 681 patients with type 2 diabetes inadequately controlled (hemoglobin A1c [HbA1c] ≥7 and ≤11%) with oral antihyperglycemic medications (OAMs). Patients added 2 mg EQW or 10 μg EBID to current OAMs. Safety was re-evaluated 10 weeks after last treatment.

RESULTS

EQW was superior to EBID on HbA1c measures at week 26 (Least-squares mean treatment difference: -0.31% [95% confidence interval -0.49, -0.14%]). More EQW-treated patients achieved target HbA1c ≤7.0% (P = 0.003), ≤6.5% (P < 0.001), or ≤6.0% (P = 0.003). Fasting serum glucose reductions were greater among EQW-treated patients (P < 0.001). Blood glucose profiles improved in both treatment groups (P < 0.001). Weight loss occurred with both treatments, but was greater with EBID. Adverse events (≥10%, either group) were nausea, injection-site induration, dyslipidemia and vomiting. Injection-site induration was more frequent with EQW, whereas nausea, vomiting and hypoglycemia were less frequent. One episode each of major hypoglycemia (EBID) and pancreatitis (EQW) were reported.

CONCLUSION

In this population, EQW and EBID showed efficacious glucose and weight control; safety and tolerability were consistent with observations in non-Asian patients. This trial was registered with ClinicalTrials.gov (no. NCT00917267).

The association of insulin resistance and carotid atherosclerosis with thigh and calf circumference in patients with type 2 diabetes

Background

The relationship between body composition parameters such as thigh and calf circumference and insulin resistance or atherosclerosis in type 2 diabetes is poorly understood. The aim of this study was to investigate the relationship between insulin resistance, atherosclerosis, and thigh and calf circumference in patients with type 2 diabetes.

Methods

A total of 4,427 subjects with type 2 diabetes were enrolled in this study. Insulin sensitivity was assessed according the rate constant for plasma glucose disappearance (Kitt) determined via the short insulin tolerance test. Biochemical and anthropometric profiles were measured according to a standardized protocol. Visceral fat thickness and carotid intima media thickness (IMT) were measured by ultrasonography.

Results

Insulin sensitivity index (Kitt) was significantly correlated with weight adjusted thigh and calf circumference. Thigh circumference was inversely associated with IMT in men and women and calf circumference was negatively correlated with IMT in women. Multiple stepwise regression analysis revealed that thigh circumference was independently correlated with insulin sensitivity index (Kitt) and IMT. Furthermore, in multivariate logistic regression analysis, thigh circumference was an independent determinant factor for carotid atherosclerosis in patients with type 2 diabetes even after adjusting for other cardiovascular risk factors.

Conclusions

Thigh and calf circumference were correlated with insulin resistance and carotid atherosclerosis, and thigh circumference was independently associated with insulin resistance and carotid atherosclerosis in patients with type 2 diabetes.

Human insulin secreted from insulinogenic xenograft restores normoglycemia in type 1 diabetic mice without immunosuppression

In the present study, we examined the therapeutic potential of human amnion-derived insulin-secreting cells for type 1 diabetes. Human amniotic mesenchymal stem cells (hAMs) were isolated from amnion and cultivated to differentiate into insulin-secreting cells in vitro. After culture in vitro, the differentiated cells (hAM-ISCs) were intensively stained with dithizone and secreted insulin and c-peptide in a high-glucose-dependent manner. They expressed mRNAs of pancreatic cell-related genes, including INS, PDX1, Nkx6-1, NEUROG3, ISL1, NEUROD1, GLUT1, GLUT2, PC1/3, PC2, GCK, PPY, SST, and GC, and were positive for human insulin and c-peptide. Transplantation of hAM-ISCs into the kidneys of mice with streptozotocin-induced diabetes restored body weight and normalized the blood glucose levels, which lasted for 210 days. Only human insulin and c-peptide were detected in the blood of normalized mice after 2 months of transplantation, but little mouse insulin and c-peptide. Removal of graft-bearing kidneys from these mice resulted in causing hyperglycemia again. Human cell-specific gene, hAlu, and human pancreatic cell-specific genes, insulin, PDX1, GLUT1, GLP1R, Nkx6-1, NEUROD1, and NEUROG3, were detected in the graft-bearing kidneys. Colocalization of human insulin and human nuclei antigen was also observed. These results demonstrate that hAMs could differentiate into functional insulin-secreting cells in vitro, and human insulin secreted from hAM-ISCs following transplantation into type 1 diabetic mice could normalize hyperglycemia, overcoming immune rejection for a long period.

Insulin resistance is independently associated with peripheral and autonomic neuropathy in Korean type 2 diabetic patients

In addition to chronic hyperglycemia, insulin resistance itself has been proposed to cause a diabetic neuropathy. We evaluated the role of insulin resistance in the pathogenesis of peripheral and autonomic neuropathy in patients with type 2 diabetes. Eighty-six patients with type 2 diabetes were evaluated for the anthropometric and biochemical profiles, and Kitt value was calculated from insulin tolerance test to assess the insulin resistance. Various autonomic function tests, nerve conduction velocity, and quantitative sensory tests were performed to assess autonomic and peripheral neuropathy. In univariate analysis, both autonomic and peripheral neuropathy were significantly associated with glycemic exposure index (GE index), HDL-cholesterol, duration of DM, and Kitt value. In stepwise linear regression analysis, GE index was an independent predictor of autonomic and peripheral neuropathy (β = 0.643, P < 0.001; β = 0.207, P = 0.013, respectively), and Kitt value was also an independent factor for the autonomic and peripheral neuropathy (β = - 0.306, P < 0.001; β = - 0.329, P < 0.001, respectively). Low HDL-cholesterol increased the odds ratio for peripheral neuropathy. Insulin resistance is independently associated with peripheral and autonomic neuropathy in Korean Type 2 diabetic patients along with hyperglycemia and HDL-cholesterol.

Dual pathways of p53 mediated glucolipotoxicity-induced apoptosis of rat cardiomyoblast cell: activation of p53 proapoptosis and inhibition of Nrf2-NQO1 antiapoptosis

Reactive oxygen species (ROS), driven by excessive levels of glucose and free fatty acids, appears to induce cell apoptosis. However, the underlying molecular mechanism of this process remains unclear in cardiac myocytes. We investigated the glucolipotoxicity effects of high glucose and palmitic acid (C16:0) on the rat cardiomyoblast cell line (H9c2) focusing on tumor suppressor p53. Cultured H9c2 rat cardiomyoblasts were exposed to palmitate and /or to an elevated glucose concentration for 18 hours. Only the glucolipotoxic condition of 30 mM glucose in combination with 250 μM palmitate resulted in significant generation of ROS and upregulation of p53 which caused to an increased cleavage of caspase-3. On the other hand, the expression of NF-E2-related factor 2 (Nrf2) showed increased tendency while the expression of NAD(P)H: quinone oxidoreductase-1 (NQO1) was decreased. N-acetyl L cysteins and pifithrin-α, an inhibitor of p53 abrogated glucolipotoxicity-induced ROS generation and p53 expression. Chromatin immunoprecipitation analysis revealed that p53 interacted antioxidant responsive elements (ARE)-containing promoter of NQO1. Upregulated p53 counteracted the Nrf2-induced transcription of ARE-containing promoter of NQO1 gene and leaded to decrease in NQO1 expression. We demonstrated that the elevated p53 mediated glucolipotoxicity-induced apoptosis of rat cardiomyoblast cell through dual pathways: stimulating pro-apoptosis signaling as well as suppressing anti-apoptosis pathway of Nrf2-NQO1 signaling.

Serum cystatin C reflects the progress of albuminuria

BACKGROUND

Research on the relationship between urinary albumin excretion and serum cystatin C in diabetes is restricted to cross-sectional studies. In this study, we investigated how well serial measurements of serum cystatin C level reflect changes in the urinary albumin excretion rate.

METHODS

We enrolled and retrospectively collected data on 1,058 participants with type 2 diabetes who were older than 18 years and who had more than 3 years of follow-up with serial measurements of albuminuria and serum cystatin C at an outpatient clinic.

RESULTS

With the use of a linear mixed model, we found that the albuminuria level for each patient over time corresponded with the annual change in serum cystatin C-based estimated glomerular filtration rate (cysC-eGFR) but did not correspond with the creatinine-based eGFR calculated by the modification of diet in renal disease formula (MDRD-eGFR). The discrepancy in the direction of the trend was smaller with cysC-eGFR than with MDRD-eGFR.

CONCLUSION

Serum cystatin C level reflects the trend in albuminuria level more accurately than serum creatinine level in Korean type 2 diabetes mellitus patients.

Korean red ginseng (Panax ginseng) improves insulin sensitivity in high fat fed Sprague-Dawley rats

Many studies have documented that ginseng has antidiabetic and antiobesity effects, but the mechanism of the effects has not been elucidated. The aim of this study was to determine the effect of Korean red ginseng (KRG, Panax ginseng) and investigate the mechanism of antidiabetic and antiobesity effects in obese insulin resistant animal models. Sprague-Dawley (SD) rats were divided into three groups: a control group (group I) fed a normal diet, another group (group II) fed only high fat diet (HFD) and a third group (group III) fed HFD with KRG (200 mg/kg, oral) for 18 weeks. The body weight, food intake, adipose tissues, liver, kidney, pancreas, adiponectin, and leptin were measured. Blood glucose, insulin tolerance test, and hyperinsulinemic euglycemic clamp test were investigated. A significant weight reduction, especially fat mass reduction, was observed in the KRG treated group. Increased insulin sensitivity was found in the KRG treated group. We observed increased insulin signalling, increased phosphorylation of IR, IRS-1, Akt, and membranous GLUT4 in muscle by Western blotting assay. In conclusion, KRG may have antidiabetic and antiobesity effects due to partly increased insulin sensitivity by increased adipokine and partly enhanced insulin signalling.

Association between γ-glutamyltransferase, adiponectin and arterial stiffness

AIM

Serum γ-glutamyltransferase (GGT) is used as a marker of hepatic dysfunction. Recently, several studies reported that GGT is significantly associated with cardiovascular mortality and atherosclerosis. Adiponectin is known to play an important role in the development of atherosclerosis, but its physiologic role has yet to be fully determined. In this study, we investigated the relationships among serum GGT, adiponectin and arterial stiffness.

METHODS

Of 4236 subjects recruited from 17 different medical centers in Seoul, Korea, 2846 subjects were enrolled in our study. The parameters of metabolic syndrome (MetS) were assessed in these subjects, and their plasma adiponectin levels and pulse wave velocity (PWV) were measured along with anthropometric and biochemical profiles, including GGT.

RESULTS

The subjects were stratified into 3 groups according to GGT values. PWV values gradually increased and the adiponectin level decreased with GGT tertiles. Aortic PWV showed a significant correlation with age, SBP, FPG, but there was no correlation among aortic PWV, GGT and adiponectin. Peripheral PWV demonstrated a significant correlation with age, SBP, DBP, BMI, WC, FPG and GGT, but there was no correlation between peripheral PWV and adiponectin. In multiple logistic regression analysis after adjusting for risk factors, GGT was a significant contributor to increased peripheral PWV.

CONCLUSIONS

These findings indicate that serum GGT is independently associated with increased arterial stiffness, but there was no correlation between adiponectin and arterial stiffness in both males and females.

Dietary oleate has beneficial effects on every step of non-alcoholic Fatty liver disease progression in a methionine- and choline-deficient diet-fed animal model

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is increasingly recognized as a major cause of liver-related morbidity and mortality. The underlying mechanisms of disease progression remain poorly understood, and primary therapy of NAFLD is not yet established. We investigated the effects of dietary oleate on the development and progression of NAFLD in a methionine- and choline-deficient (MCD) diet-fed animal model.

METHODS

A total of 30 C57BL/6J mice were randomly divided into three groups (n=10 in each group) and fed various experimental diets for four weeks: chow, MCD diet, or OMCD (MCD diet with oleate, 0.5 mg/g/day). Liver samples were examined for steatohepatitis and fibrosis parameters and associated genes.

RESULTS

Additional dietary oleate dramatically reduced MCD diet-induced hepatic steatosis. Hepatic carbohydrate responsive element-binding protein was overexpressed in MCD diet-fed mice, and dietary oleate prevented this overexpression (P<0.001). Dietary oleate partially prevented MCD diet-induced serum level increases in aspartate aminotransferase and alanine aminotransferase (P<0.001, respectively). The mRNA expressions of hepatic monocyte chemoattractant protein 1, tumor necrosis factor-α and matrix metalloproteinase-9 were increased in MCD diet-fed mice, and this overexpression of inflammatory molecules was prevented by dietary oleate (P<0.001). Hepatic pericellular fibrosis was observed in MCD diet-fed mice, and dietary oleate prevented this fibrosis. Altogether, dietary oleate prevented MCD diet-induced hepatic steatosis, inflammation and fibrosis.

CONCLUSION

Dietary oleate has beneficial effects in every step of NAFLD development and progression and could be a nutritional option for NAFLD prevention and treatment.

Serum uric acid level is associated with metabolic syndrome and microalbuminuria in Korean patients with type 2 diabetes mellitus

AIMS

To determine the relationship between serum uric acid, metabolic syndrome (MetS), and albuminuria in type 2 diabetic patients.

METHODS

A total of 504 Korean patients with type 2 diabetes aged 57.3 years were retrospectively evaluated for clinical histories, anthropometric measurements, and biochemical studies. Urinary albumin excretion (UAE) was measured by a 24-h urine collection.

RESULTS

Prevalence of MetS increased according to the quartiles of uric acid levels (≤3.7, 3.8 to 4.5, 4.6 to 5.5, and >5.5 mg/dl; 52.1%, 52.1%, 57.5%, and 71.6%, respectively, P<.001). Individual components of MetS (abdominal obesity, hypertriglyceridemia, low HDL-cholesterol, high blood pressure) were also significantly associated with the highest quintile of uric acid levels. Serum uric acid levels had significantly increased risk of albuminuria [odds ratio (OR) 1.425, 95% confidence interval (CI) 1.085-1.873] after adjusting for age, gender, and conventional risk factors. Uric acid level remains a significant predictor for abnormal albuminuria after adjusting for MetS presence as well as the use of angiotensin-converting enzyme inhibitor (ACEI) or angiotensin II receptor blocker (ARB) (OR 1.414, 95% CI 1.071-1.868).

CONCLUSION

An elevated uric acid level was significantly associated with MetS and was an independent predictor of albuminuria after adjusting for conventional risk factors and MetS. Regular measurements of uric acid level could give information for predicting the presence of MetS and albuminuria in Korean type 2 diabetic patients.

The humoral immune response to the inactivated influenza A (H1N1) 2009 monovalent vaccine in patients with Type 2 diabetes mellitus in Korea

AIMS

We evaluated the antibody response to a single-dose adjuvanted, inactivated, pandemic H1N1 influenza vaccination in patients with diabetes and assessed factors associated with the failure to induce antibody responses.

METHODS

Eighty-two patients with Type 2 diabetes were vaccinated and antibody responses were determined with haemagglutination inhibition assay and anti-haemagglutinin antibody ELISA.

RESULTS

Among 70 antibody-negative patients at baseline, 34 (48.6%) achieved seroconversion; 28 (60.9%) in the young adults group and six (25%) in the elderly group acquired H1N1-specific antibodies. Patients in the older age range or with longer duration of diabetes had a lower seroconversion rate.

CONCLUSIONS

Our data show low cross-reactive antibody carrying rate and low seroconversion rate in patients with diabetes. Until larger-scale, case-controlled trials become available, older patients and patients with a longer duration of diabetes should be considered for the two-dose vaccination or have antibody titres measured after the first vaccination.

Up-regulation of hepatic low-density lipoprotein receptor-related protein 1: a possible novel mechanism of antiatherogenic activity of hydroxymethylglutaryl-coenzyme A reductase inhibitor Atorvastatin and hepatic LRP1 expression

Low-density lipoprotein receptor-related protein 1 (LRP1) binds to apolipoprotein E and serves as a receptor for remnant lipoproteins in the liver, thus playing an important role in clearing these atherogenic particles. In this study, we investigated the effect of atorvastatin, a hydroxymethylglutaryl-coenzyme A reductase inhibitor, on hepatic LRP1 expression. We used HepG2 and Hep3B cells for in vitro study, and Otsuka Long-Evans Tokushima fatty and Sprague-Dawley rats for in vivo study. We used relatively high pharmacologic dose of atorvastatin in this study (in vitro, 0.5 μmol/L in culture media, for 48 hours; in vivo, 20 mg/[kg d], for 6 weeks). Atorvastatin increased LRP1 and low-density lipoprotein (LDL) receptor expression in HepG2 and Hep3B cells and induced hepatic LRP1 and LDL receptor expression in chow diet-fed Sprague-Dawley rats and high-fat diet-fed Otsuka Long-Evans Tokushima fatty rats. Atorvastatin decreased intracellular sterol level and increased the amount of the nuclear form of sterol response element-binding protein-2 (SREBP-2) in both HepG2 and Hep3B cells as well as in two animal models. Treatment of HepG2 cells with LDL increased intracellular sterol level and reduced LRP1, LDL receptor, and SREBP-2. When SREBP-2 in HepG2 cells was knocked down by small interfering RNA, the induction of LRP1 expression by atorvastatin did not take place. In conclusion, up-regulation of hepatic LRP1 might be a novel mechanism by which statin treatment decreases remnant lipoproteins. In addition, SREBP-2 acts as a mediator of atorvastatin-induced up-regulation of hepatic LRP1. Future studies using standard doses of atorvastatin in humans are needed to elucidate clinical relevance of these findings.

Diabetic peripheral neuropathy is associated with increased arterial stiffness without changes in carotid intima-media thickness in type 2 diabetes

OBJECTIVE

This study was conducted to investigate the association of diabetic peripheral neuropathy (DPN) with both arterial stiffness and intima-media thickness (IMT).

RESEARCH DESIGN AND METHODS

We conducted a cross-sectional analysis of 731 subjects with type 2 diabetes. DPN was diagnosed on the basis of neuropathic symptoms, insensitivity to a 10-g monofilament, abnormal pin-prick sensation, and abnormal current perception threshold. Arterial stiffness was assessed by cardio-ankle vascular index (CAVI), and IMT was assessed by B-mode ultrasonography.

RESULTS

Patients with DPN had higher CAVI than those without DPN in multivariate-adjusted models, whereas no differences in IMT were observed between patients with and without DPN after adjustment for age and sex. In the multivariate analysis, CAVI was a significant determinant of DPN (odds ratio 1.36 [95% CI 1.13-1.65], P = 0.001).

CONCLUSIONS

DPN is significantly associated with arterial stiffness without carotid intimal changes in patients with type 2 diabetes.

Predictive clinical parameters for the therapeutic efficacy of sitagliptin in korean type 2 diabetes mellitus

BACKGROUND

Sitagliptin is a highly selective dipeptidyl peptide-4 (DPP-4) inhibitor that increases blood levels of active glucagon-like peptide (GLP)-1 and glucose-dependent insulinotrophic polypeptide (GIP), resulting in increased insulin secretion. While studies conducted in other countries have indicated the efficacy and safety of using sitagliptin to treat type 2 diabetes mellitus (T2DM), its predictors of effects to sitagliptin are not well understood. Therefore, we evaluated the predictive clinical parameters for the therapeutic benefits of sitagliptin when added to an ongoing metformin or sulfonylurea therapy in Korean T2DM subjects.

METHODS

We obtained data from 251 Korean T2DM subjects who had recently started taking sitagliptin as add-on therapy. Exclusion criteria included any insulin use. Changes in HbA1c (ΔHbA1c) and fasting plasma glucose (ΔFPG) were assessed by comparing baseline levels prior to sitagliptin administration to levels 12 and 24 weeks after treatment. Responders were defined as subjects who experienced decrease from baseline of >10% in ΔHbA1c or >20% in ΔFPG levels at 24 weeks.

RESULTS

We classified 81% of the subjects (204 out of 251) as responders. The responder group had a lower mean body mass index (23.70±2.40 vs. 26.00±2.26, P≤0.01) and were younger (58.83±11.57 years vs. 62.87±12.09 years, P=0.03) than the non-responder group.

CONCLUSION

In Korean T2DM subjects, sitagliptin responders had lower body mass index and were younger compared to non-responders.

Fat redistribution preferentially reflects the anti-inflammatory benefits of pioglitazone treatment

Thiazoledinedione is known to have an anti-inflammatory effect besides a hypoglycemic effect. We investigated changes in high-sensitivity C-reactive protein (hsCRP), a proinflammatory marker, after pioglitazone treatment in association with the resulting changes in various metabolic and anthropometric parameters. A total of 93 type 2 diabetes mellitus patients (47 men and 46 women; mean age, 50.0 ± 10.8 years) who were being treated with a stable dose of sulfonylurea or metformin were enrolled in the study. Pioglitazone (15 mg/d) was added to their treatment regimen for 12 weeks, and metabolic and anthropometric measurements were taken before and after pioglitazone treatment. Pioglitazone treatment for 12 weeks decreased serum hsCRP levels (0.83 [1.14] to 0.52 [0.82] mg/L, P < .001) and improved glycemic control (fasting glucose, P < .001; glycosylated hemoglobin, P < .001) and lipid profiles (triglyceride, P = .016; high-density lipoprotein cholesterol, P < .001). Between responders and nonresponders to the hsCRP-lowering effect of pioglitazone, there were significant differences in baseline hsCRP levels and changes in the postprandial glucose and the ratio of visceral fat thickness (VFT) to subcutaneous fat thickness (SFT) (P = .004, .011, and .001, respectively). The percentage change in hsCRP levels after treatment was inversely correlated with baseline hsCRP levels (r = -0.497, P < .001) and directly correlated with the change in postprandial glucose (r = 0.251, P = .021), VFT (r = 0.246, P = .030), and VFT/SFT ratio (r = 0.276, P = .015). Logistic regression analysis revealed that the hsCRP-lowering effect of pioglitazone was affected by baseline hsCRP levels (odds ratio [OR] = 7.929, P = .007) as well as changes in postprandial 2-hour glucose (OR = 0.716, P = .025) and VFT/SFT ratio (OR = 0.055, P = .009). In conclusion, treatment with pioglitazone produced an anti-inflammatory effect, decreasing serum hsCRP levels; and a decrease in the VFT/SFT ratio was independently and most strongly associated with the hsCRP-decreasing effect. These results suggest that abdominal fat redistribution preferentially reflects the anti-inflammatory benefits of pioglitazone treatment.

Effect of pioglitazone on serum concentrations of osteoprotegerin in patients with type 2 diabetes mellitus

OBJECTIVE

Osteoprotegerin (OPG) acts as an important regulatory molecule in atherosclerosis. Recent studies report that thiazolidinediones could affect OPG expression. We investigated the relationship between OPG and inflammatory cytokines and the effects of pioglitazone (a PPARγ (PPARG) agonist) versus metformin on serum OPG levels in type 2 diabetic patients.

DESIGN AND METHODS

Sixty-seven type 2 diabetic patients were included in this study. They were assigned to pioglitazone (15 mg/day, n=34) or metformin (1000 mg/day, n=33) during 24 weeks. Various anthropometric and metabolic parameters, OPG, interleukin 6 (IL6), C-reactive protein (CRP), adiponectin, and homeostasis model assessment of insulin resistance (HOMA-IR), were measured at baseline and at 6 months of treatment.

RESULTS

Serum OPG levels correlated significantly with fasting plasma glucose (FPG), HbAlc, HOMA-IR, IL6, and CRP, and inversely correlated with adiponectin after adjusting for age (P<0.05). Multiple regression analysis showed that FPG, HbAlc, and adioponectin were independently correlated with OPG level. After 6 months of treatment, the reduction in FPG and HbAlc levels was similar between the two groups. Pioglitazone treatment significantly increased body mass index (P<0.05) and waist circumference (P<0.05) and decreased triglycerides (P<0.05) and HOMA-IR (P<0.01). The adiponectin concentration was increased (P<0.05), and OPG and CRP levels were decreased in the pioglitazone group (P<0.05), but were unchanged in the metformin group. The changes in serum OPG in the pioglitazone group showed significant correlation with changes in FPG, HbAlc, and adiponectin.

CONCLUSIONS

In type 2 diabetic patients, pioglitazone decreases OPG levels, and this decrease in OPG levels might be associated with the increase in adiponectin.

Regulation of pancreatic islet gene expression in mouse islets by pregnancy

Pancreatic β cells adapt to pregnancy-induced insulin resistance by unclear mechanisms. This study sought to identify genes involved in β cell adaptation during pregnancy. To examine changes in global RNA expression during pregnancy, murine islets were isolated at a time point of increased β cell proliferation (E13.5), and RNA levels were determined by two different assays (global gene expression array and G-protein-coupled receptor (GPCR) array). Follow-up studies confirmed the findings for select genes. Differential expression of 110 genes was identified and follow-up studies confirmed the changes in select genes at both the RNA and protein level. Surfactant protein D (SP-D) mRNA and protein levels exhibited large increases, which were confirmed in murine islets. Cytokine-induced expression of SP-D in islets was also demonstrated, suggesting a possible role as an anti-inflammatory molecule. Complementing these studies, an expression array was performed to define pregnancy-induced changes in expression of GPCRs that are known to impact islet cell function and proliferation. This assay, the results of which were confirmed using real-time reverse transcription-PCR assays, demonstrated that free fatty acid receptor 2 and cholecystokinin receptor A mRNA levels were increased at E13.5. This study has identified multiple novel targets that may be important for the adaptation of islets to pregnancy.

Dietary monounsaturated fatty acids but not saturated fatty acids preserve the insulin signaling pathway via IRS-1/PI3K in rat skeletal muscle

Saturated fatty acids (SFA) and monounsaturated fatty acids (MUFA) show different effects on the development of insulin resistance. In this study, we compared the effect of dietary SFA and MUFA on the insulin signaling pathway in the skeletal muscle of a type 2 diabetic animal model. Twenty-nine-week-old male Otsuka Long-Evans Tokushima fatty (OLETF) rats were randomly divided into three groups and fed one of the following diets for 3 weeks; a normal chow diet, an SFA (lard oil) enriched or a MUFA (olive oil) enriched high-fat diet. The vastus lateralis muscle was used for analyses. Insulin tolerance test showed improved insulin sensitivity in rats fed the MUFA diet, as compared to those fed the SFA diet (p < 0.001). The SFA diet reduced IRS-1 expression and phosphorylated PI3K levels in skeletal muscle, as compared with a chow diet (p < 0.001, respectively). On the contrary, muscle IRS-2 expression and phosphorylated ERK1/2 was significantly increased in rats fed the SFA diet (p < 0.001, respectively). Membrane translocation of glucose transporter type 4 decreased in the skeletal muscle of rats fed the SFA diet, as compared to those fed a chow diet (p < 0.001). These changes in insulin signaling pathway in skeletal muscle were not observed in rats fed the MUFA diet. In conclusion, the beneficial effect of dietary MUFA on insulin sensitivity is associated with a conserved IRS-1/PI3K insulin signaling pathway which was altered by dietary SFA.

Visceral adiposity and leptin are independently associated with C-reactive protein in Korean type 2 diabetic patients

The inflammatory marker, C-reactive protein (CRP) is associated with long-term cardiovascular events. The aim of the study was to investigate the factors contributing to serum CRP, assess the relationship between CRP level and the parameters of visceral obesity, and examine the association between leptin and CRP level in type 2 diabetic patients. 150 patients with type 2 diabetes were enrolled. These patients were recently diagnosed (< or =3 years) with type 2 diabetes and were drug naive or taking sulfonylureas only. BMI, WC, and serum concentration of CRP, glycosylated hemoglobin (HbA1c), glucose, lipids, plasminogen activator-1 (PAI-1) and leptin were measured. Insulin resistance was estimated by the insulin resistance index of homeostasis model assessment (HOMA-IR). We measured the carotid intima-media thickness (IMT). Fat mass assessed by dual-energy X-ray absorptionmetry and abdominal fat distribution was determined by CT scan. Serum concentration of CRP was significantly correlated with BMI (gamma = 0.257, P < 0.01), WC (gamma = 0.293, P < 0.01), fat mass (gamma = 0.213, P < 0.01), total adipose tissue (gamma = 0.263, P < 0.01), visceral adipose tissue (gamma = 0.296, P < 0.01), insulin (gamma = 0.189, P = 0.047), PAI-1 (gamma = 0.206, P < 0.01), leptin (gamma = 0.322, P < 0.01), mean IMT (gamma = 0.132, P = 0.042), and HOMA-IR (gamma = 0.172, P = 0.045). After adjustment for age and gender, multiple regression analysis showed that serum CRP was significantly associated with leptin (beta = 0.326, P = 0.01) and visceral adipose tissue (beta = 0.265, P = 0.035). In conclusion, serum CRP level is significantly associated with obesity, especially the visceral adipose tissue, and serum leptin is another important independent factor associated with CRP in Korean type 2 diabetic patients.

Adiponectin is independently associated with apolipoprotein B to A-1 ratio in Koreans

Apolipoprotein B to A-1 (apo B/A-1) ratio is reportedly a better predictor of atherosclerotic vascular disease than low-density lipoprotein cholesterol (LDL-C). The aim of this study was to assess the association of serum apo B/A-1 ratio with insulin resistance and adiponectin in patients with different grades of glucose intolerance. Patients were divided according to glucose tolerance into 3 groups: normal glucose tolerance without metabolic syndrome (n = 229), impaired fasting glucose (subjects with fasting plasma glucose level between 100 and 125 mg/dL, n = 658), and type 2 diabetes mellitus (n = 381). Serum concentrations of apo B, apo A-1, glucose, total cholesterol (TC), triglycerides, and high-density lipoprotein cholesterol (HDL-C) and adiponectin were measured. Insulin resistance was estimated by the homeostasis model assessment of insulin resistance index (HOMA-IR). There were significant differences in metabolic parameters among the groups, including waist circumference, insulin, HOMA-IR, and apo B/A-1 ratio, which increased sequentially with glucose intolerance, whereas adiponectin level decreased with increasing severity of glucose intolerance. The apo B/A-1 ratio was significantly correlated with TC, triglycerides, LDL-C, HDL-C, adiponectin, and HOMA-IR in normal glucose tolerance, impaired fasting glucose, and type 2 diabetes mellitus. Multiple regression analysis showed that apo B/A-1 ratio was significantly associated with TC, LDL-C, HDL-C, and adiponectin. In conclusion, apo B/A-1 ratio was significantly associated with insulin resistance according to glucose intolerance; and serum adiponectin was an important independent factor associated with apo B/A-1 ratio in Koreans.

A low-risk ZnT-8 allele (W325) for post-transplantation diabetes mellitus is protective against cyclosporin A-induced impairment of insulin secretion

SLC30A8 encodes the β-cell-specific zinc transporter-8 (ZnT-8) expressed in insulin secretory granules. The single-nucleotide polymorphism rs13266634 of SLC30A8 is associated with susceptibility to post-transplantation diabetes mellitus (PTDM). We tested the hypothesis that the polymorphic residue at position 325 of ZnT-8 determines the susceptibility to cyclosporin A (CsA) suppression of insulin secretion. INS (insulinoma)-1E cells expressing the W325 variant showed enhanced glucose-stimulated insulin secretion (GSIS) and were less sensitive to CsA suppression of GSIS. A reduced number of insulin granule fusion events accompanied the decrease in insulin secretion in CsA-treated cells expressing ZnT-8 R325; however, ZnT-8 W325-expressing cells exhibited resistance to the dampening of insulin granule fusion by CsA, and transported zinc ions into secretory vesicles more efficiently. Both tacrolimus and rapamycin caused similar suppression of GSIS in cells expressing ZnT-8 R325. However, cells expressing ZnT-8 W325 were resistant to tacrolimus, but not to rapamycin. The Down's syndrome candidate region-1 (DSCR1), an endogenous calcineurin inhibitor, overexpression and subsequent calcineurin inhibition significantly reduced GSIS in cells expressing the R325 but not the W325 variant, suggesting that differing susceptibility to CsA may be due to different interactions with calcineurin. These data suggest that the ZnT-8 W325 variant is protective against CsA-induced suppression of insulin secretion. Tolerance of ZnT-8 W325 to calcineurin activity may account for its protective effect in PTDM.

The effect of mosapride (5HT-4 receptor agonist) on insulin sensitivity and GLUT4 translocation

AIMS

We investigated the effect of mosapride, 5HT-4 (5-hydroxytryptamine) agonist, on blood glucose level and insulin sensitivity in subjects with impaired glucose tolerance (IGT) and conducted an in vitro study to evaluate the action mechanism.

METHODS

Thirty IGT patients were randomly assigned to receive either mosapride or placebo for 2 weeks. Biochemical profiles and insulin sensitivity index from euglycemic hyperinsulinemic clamp test were assessed before and after treatment. In cultured myotubes from human skeletal muscle cells, insulin- and mosapride-induced GLUT4 translocation and tyrosine phosphorylation of IRS-1 were determined.

RESULTS

After 2 weeks of treatment with mosapride, glucose disposal rates were significantly increased up to those of control (mosapride 5.47+/-1.72 vs 7.06+/-2.13, P=0.004, placebo 5.42+/-1.85 vs 5.23+/-1.53mgkg(-1)min(-1)). Fasting plasma glucose (FPG) and insulin levels were decreased. Mosapride increased the contents of GLUT4 in plasma membrane representing the increased recruitment of glucose transporters from intracellular pool. While insulin treatment on human skeletal muscle cell resulted in an increased tyrosine phosphorylation of IRS-1, mosapride did not have any effect.

CONCLUSIONS

Mosapride is effective in decreasing FPG without stimulating insulin secretion in IGT subjects, possibly by inducing GLUT4 translocation in skeletal muscles.

The effect of rosiglitazone on insulin sensitivity and mid-thigh low-density muscle in patients with Type 2 diabetes

AIMS

We examined the effect of rosiglitazone on insulin sensitivity, abdominal fat and mid-thigh intramuscular fat distribution, and plasma concentrations of adipocytokines in patients with Type 2 diabetes.

METHODS

Rosiglitazone was administered at a daily dose of 4 mg to 42 Type 2 diabetes patients [age 32-70 years, body mass index (BMI) 17.5-32.6 kg/m(2), 15 women, 27 men] for 12 weeks. Various anthropometric and metabolic profiles, plasma adiponectin, leptin, and resistin levels were measured, and insulin resistance was calculated from the short insulin tolerance test. Body fat composition was assessed by computed tomography.

RESULTS

Twelve weeks' rosiglitazone treatment resulted in improved insulin resistance despite increases in body weight and BMI. There was a significant decrease in abdominal visceral adipose tissue area (145 +/- 65.6 vs. 129 +/- 73.1 cm(2), P = 0.049). Mid-thigh low-density muscle area (TLDMA) increased from 23 +/- 9.6 to 26 +/- 8.2 cm(2) (P = 0.009). There were significant changes in plasma adipocytokines, but they were not significantly correlated with changes in insulin resistance.

CONCLUSIONS

Rosiglitazone treatment resulted in an improvement of insulin responsiveness in Type 2 diabetic subjects, which was associated with the redistribution of visceral and subcutaneous adipose tissue, an increase in TLDMA, and changes in serum adipocytokine levels. Further studies are needed to elucidate the insulin sensitizing mechanism of rosiglitazone on peripheral skeletal muscles.

Nerve growth factor and expression of its receptors in patients with diabetic neuropathy

AIMS

Low serum nerve growth factor (NGF) levels have been reported in patients with diabetic peripheral neuropathy (DPN), but the role of NGF in the development of neuropathy is unclear. Thus, we investigated the associations of serum NGF level and NGF receptor activity with the presence and severity of DPN.

METHODS

One hundred and thirty-six patients with Type 2 diabetes were included in this cross-sectional study. Serum NGF levels were measured by ELISA. Expressions of NGF receptors (TrkA and p75(NTR)) were measured by immunohistochemical staining. The presence and severity of DPN were assessed by neuropathy disability score (NDS) and by corneal nerve fibre length (cNFL) and nerve branch density (cNBD) using in vivo confocal microscopy.

RESULTS

Patients with DPN had higher serum NGF levels (56-451 pg/ml) than patients without DPN (4-54 pg/ml). However, in DPN patients, serum NGF was negatively associated with neuropathy severity (mild 222 +/- 64 pg/ml; moderate 114 +/- 17 pg/ml; severe 89 +/- 20 pg/ml). This negative association was consistent in all severity indices (NDS, P < 0.001; cNFL, P < 0.001; cNBD P = 0.010) even after adjustment for age, sex, diabetes duration, insulin use, fasting glucose and glycated haemoglobin. Although NGF receptor activities had significantly (P < 0.05) negative associations with the presence and severity of neuropathy, these associations were not significant when adjusted for other factors.

CONCLUSIONS

Serum NGF level was positively associated with the presence of DPN but negatively associated with neuropathy severity in DPN patients. The change in serum NGF might be a consequence of, rather than a contributor to, the early development of DPN.

Korean red ginseng (Panax ginseng) improves insulin sensitivity and attenuates the development of diabetes in Otsuka Long-Evans Tokushima fatty rats

Ginseng has been reported to ameliorate hyperglycemia in experimental and clinical studies; however, its mechanism of action remains unclear. In this study, we investigated the metabolic effects and putative molecular mechanisms of Korean red ginseng (KRG, Panax ginseng) in animal models for type 2 diabetes mellitus (T2DM) and peripheral insulin-responsive cell lines. Korean red ginseng was administered orally at a dose of 200 mg/(kg d) to Otsuka Long-Evans Tokushima fatty rats for 40 weeks. Initially, chronic administration of KRG reduced weight gain and visceral fat mass in the early period without altering food intake. The KRG-treated Otsuka Long-Evans Tokushima fatty rats showed improved insulin sensitivity and significantly preserved glucose tolerance compared with untreated control animals up to 50 weeks of age, implying that KRG attenuated the development of overt diabetes. KRG promoted fatty acid oxidation by the activation of adenosine monophosphate-activated protein kinase (AMPK) and phosphorylation of acetyl-coenzyme A carboxylase in skeletal muscle and cultured C2C12 muscle cells. Increased expression of peroxisome proliferator-activated receptor-gamma coactivator-1alpha, nuclear respiratory factor-1, cytochrome c, cytochrome c oxidase-4, and glucose transporter 4 by KRG treatment indicates that activated AMPK also enhanced mitochondrial biogenesis and glucose utilization in skeletal muscle. Although these findings suggest that KRG is likely to have beneficial effects on the amelioration of insulin resistance and the prevention of T2DM through the activation of AMPK, further clinical studies are required to evaluate the use of KRG as a supplementary agent for T2DM.

Usefulness of brachial-ankle pulse wave velocity as a predictive marker of multiple coronary artery occlusive disease in Korean type 2 diabetes patients

Multiple coronary artery occlusive disease (multiple CAOD) is the most fatal and frequently observed coronary artery disease in type 2 diabetes patients, but no simple, non-invasive screening tool is available yet. The aim of this study is to evaluate the arterial stiffness in type 2 diabetes patients using brachial-ankle pulse wave velocity (baPWV), to demonstrate the correlation between arterial stiffness and multiple CAOD, and to suggest the cutoff point of baPWV for predicting multiple CAOD in Korean type 2 diabetes patients. One hundred and eighty-one diabetes and 262 non-diabetes patients were enrolled in the study. Routine anthropometric and serologic data were collected. baPWV was measured the day before coronary angiography, and the severity of CAOD was assessed with Gensini score after angiography. baPWV and Gensini score were significantly increased in diabetes patients and Gensini score had a positive correlation with baPWV. Subjects in the highest tertile of baPWV showed odds ratio of 3.06 for multiple CAOD compared to the lowest tertile. In ROC curve, baPWV at 1635 cm/s showed 73% sensitivity and 75% specificity with AUC 0.76 in diabetes patients in detecting multiple CAOD. Therefore, baPWV may be utilized a screening tool for predicting multiple CAOD, especially in type 2 diabetes patients.

Relationship of low-density lipoprotein (LDL) particle size to thyroid function status in Koreans

OBJECTIVE

Dyslipidaemia is a well-known manifestation of thyroid dysfunction. Recently, small low-density lipoprotein (LDL) particle size has been linked with development of cardiovascular disease. To better understand the effects of thyroid dysfunction on the development of cardiovascular disease, we examined LDL particle size and lipid profiles in subjects with different thyroid function.

METHODS

Included were 46 patients with overt hypothyroidism, 57 patients with subclinical hypothyroidism, 46 patients with overt hyperthyroidism, 51 patients with subclinical hyperthyroidism, and 110 age- and sex-matched healthy control subjects. We measured LDL particle size and lipid profiles in these subjects.

RESULTS

No significant differences were found in LDL particle size between the groups with different thyroid function. Serum total cholesterol and LDL-cholesterol levels were significantly higher in the cases of hypothyroidism than in the cases of hyperthyroidism and the healthy control subjects. Serum triglyceride levels were higher in subjects with overt hypothyroidism than in those with overt hyperthyroidism or healthy control subjects.

CONCLUSIONS

LDL particle size, the emerging risk factor for atherosclerosis, did not appear to be significantly affected by the degree of thyroid dysfunction. Increased risk of atherosclerosis in hypothyroidism does not appear to be associated with LDL particle size, the non-traditional cardiovascular risk factor.